Sparkling water is a blanket term for water in which carbon dioxide gas has been dissolved. This creates carbonation, or bubbles. Sparkling water may be plain, or may be flavored or have nutrients or salts added.

Sparkling water has been around since the late-18th century. At that time, Joseph Priestley found that by suspending a bucket of water over beer vats, the water became impregnated with bubbles and was given a pleasing taste. He later came up with a method of dripping sulfuric acid on to chalk to make the carbon dioxide and put it into the water. Around the same time a Swiss chemist came up with his own method for making sparkling water, trying to recreate the healing waters of natural sparkling springs which could be distributed more cheaply.

Modern sparkling water is substantially more carbonated than these past types, as it pressurizes the carbon dioxide first, then pushes it into the water, allowing much greater densities of the gas. Historically many homes had a seltzer bottle, which used a small canister of carbon dioxide to carbonize the water as it passed through and into the glass. These days seltzer bottles are rare, but sparkling water is mass produced throughout the world and is readily available in most Western nations.

Tonic water is a specific type of sparkling water, which has quinine added to it. Originally quinine was added to sparkling water to help ward off malaria, and a taste was eventually developed for it, so that it continued to be consumed even in areas where malaria was not a significant concern. The Colonial British in India mixed their tonic water with gin to offset the medicinal taste, leading to the gin and tonic, which is today one of the most popular mixed drinks in the world. Modern tonic water has very little quinine, so that the primary taste is still of sparkling water, unlike historical tonic water, which had medical levels of quinine.

Mineral water is another specific type of sparkling water. In this case, mineral water has more than 250 parts per million of some sort of mineral dissolved in the water. Some mineral water is specifically designed to include minerals added for health reasons, but the majority of mineral waters on the market today add the minerals simply for the flavor.

Sparkling waters may also include the addition of syrups. This makes them more like sodas, although the level of sugar in them is still quite low compared to most soft drinks. Fruit flavors are the most common type of syrups used with sparkling water, although more esoteric flavors may also be found, particularly in Europe.

There have been some concerns about the effects of sparkling water on both bone density and tooth decay. Studies seem to show that although the rate at which sparkling water dissolves teeth is somewhat greater than normal water, it is still minimal enough to be of little concern. Similarly, the net effect of sparkling water on stripping calcium from the body is extremely low, making it roughly analogous to still water.